1 // SPDX-License-Identifier: GPL-2.0-only
3 * Generic helpers for smp ipi calls
5 * (C) Jens Axboe <jens.axboe@oracle.com> 2008
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 #include <linux/irq_work.h>
11 #include <linux/rcupdate.h>
12 #include <linux/rculist.h>
13 #include <linux/kernel.h>
14 #include <linux/export.h>
15 #include <linux/percpu.h>
16 #include <linux/init.h>
17 #include <linux/interrupt.h>
18 #include <linux/gfp.h>
19 #include <linux/smp.h>
20 #include <linux/cpu.h>
21 #include <linux/sched.h>
22 #include <linux/sched/idle.h>
23 #include <linux/hypervisor.h>
24 #include <linux/sched/clock.h>
25 #include <linux/nmi.h>
26 #include <linux/sched/debug.h>
29 #include "sched/smp.h"
31 #define CSD_TYPE(_csd) ((_csd)->node.u_flags & CSD_FLAG_TYPE_MASK)
33 struct call_function_data
{
34 call_single_data_t __percpu
*csd
;
35 cpumask_var_t cpumask
;
36 cpumask_var_t cpumask_ipi
;
39 static DEFINE_PER_CPU_ALIGNED(struct call_function_data
, cfd_data
);
41 static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head
, call_single_queue
);
43 static void flush_smp_call_function_queue(bool warn_cpu_offline
);
45 int smpcfd_prepare_cpu(unsigned int cpu
)
47 struct call_function_data
*cfd
= &per_cpu(cfd_data
, cpu
);
49 if (!zalloc_cpumask_var_node(&cfd
->cpumask
, GFP_KERNEL
,
52 if (!zalloc_cpumask_var_node(&cfd
->cpumask_ipi
, GFP_KERNEL
,
54 free_cpumask_var(cfd
->cpumask
);
57 cfd
->csd
= alloc_percpu(call_single_data_t
);
59 free_cpumask_var(cfd
->cpumask
);
60 free_cpumask_var(cfd
->cpumask_ipi
);
67 int smpcfd_dead_cpu(unsigned int cpu
)
69 struct call_function_data
*cfd
= &per_cpu(cfd_data
, cpu
);
71 free_cpumask_var(cfd
->cpumask
);
72 free_cpumask_var(cfd
->cpumask_ipi
);
73 free_percpu(cfd
->csd
);
77 int smpcfd_dying_cpu(unsigned int cpu
)
80 * The IPIs for the smp-call-function callbacks queued by other
81 * CPUs might arrive late, either due to hardware latencies or
82 * because this CPU disabled interrupts (inside stop-machine)
83 * before the IPIs were sent. So flush out any pending callbacks
84 * explicitly (without waiting for the IPIs to arrive), to
85 * ensure that the outgoing CPU doesn't go offline with work
88 flush_smp_call_function_queue(false);
93 void __init
call_function_init(void)
97 for_each_possible_cpu(i
)
98 init_llist_head(&per_cpu(call_single_queue
, i
));
100 smpcfd_prepare_cpu(smp_processor_id());
103 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
105 static DEFINE_PER_CPU(call_single_data_t
*, cur_csd
);
106 static DEFINE_PER_CPU(smp_call_func_t
, cur_csd_func
);
107 static DEFINE_PER_CPU(void *, cur_csd_info
);
109 #define CSD_LOCK_TIMEOUT (5ULL * NSEC_PER_SEC)
110 static atomic_t csd_bug_count
= ATOMIC_INIT(0);
112 /* Record current CSD work for current CPU, NULL to erase. */
113 static void csd_lock_record(call_single_data_t
*csd
)
116 smp_mb(); /* NULL cur_csd after unlock. */
117 __this_cpu_write(cur_csd
, NULL
);
120 __this_cpu_write(cur_csd_func
, csd
->func
);
121 __this_cpu_write(cur_csd_info
, csd
->info
);
122 smp_wmb(); /* func and info before csd. */
123 __this_cpu_write(cur_csd
, csd
);
124 smp_mb(); /* Update cur_csd before function call. */
125 /* Or before unlock, as the case may be. */
128 static __always_inline
int csd_lock_wait_getcpu(call_single_data_t
*csd
)
130 unsigned int csd_type
;
132 csd_type
= CSD_TYPE(csd
);
133 if (csd_type
== CSD_TYPE_ASYNC
|| csd_type
== CSD_TYPE_SYNC
)
134 return csd
->node
.dst
; /* Other CSD_TYPE_ values might not have ->dst. */
139 * Complain if too much time spent waiting. Note that only
140 * the CSD_TYPE_SYNC/ASYNC types provide the destination CPU,
141 * so waiting on other types gets much less information.
143 static __always_inline
bool csd_lock_wait_toolong(call_single_data_t
*csd
, u64 ts0
, u64
*ts1
, int *bug_id
)
149 call_single_data_t
*cpu_cur_csd
;
150 unsigned int flags
= READ_ONCE(csd
->node
.u_flags
);
152 if (!(flags
& CSD_FLAG_LOCK
)) {
153 if (!unlikely(*bug_id
))
155 cpu
= csd_lock_wait_getcpu(csd
);
156 pr_alert("csd: CSD lock (#%d) got unstuck on CPU#%02d, CPU#%02d released the lock.\n",
157 *bug_id
, raw_smp_processor_id(), cpu
);
162 ts_delta
= ts2
- *ts1
;
163 if (likely(ts_delta
<= CSD_LOCK_TIMEOUT
))
166 firsttime
= !*bug_id
;
168 *bug_id
= atomic_inc_return(&csd_bug_count
);
169 cpu
= csd_lock_wait_getcpu(csd
);
170 if (WARN_ONCE(cpu
< 0 || cpu
>= nr_cpu_ids
, "%s: cpu = %d\n", __func__
, cpu
))
174 cpu_cur_csd
= smp_load_acquire(&per_cpu(cur_csd
, cpux
)); /* Before func and info. */
175 pr_alert("csd: %s non-responsive CSD lock (#%d) on CPU#%d, waiting %llu ns for CPU#%02d %pS(%ps).\n",
176 firsttime
? "Detected" : "Continued", *bug_id
, raw_smp_processor_id(), ts2
- ts0
,
177 cpu
, csd
->func
, csd
->info
);
178 if (cpu_cur_csd
&& csd
!= cpu_cur_csd
) {
179 pr_alert("\tcsd: CSD lock (#%d) handling prior %pS(%ps) request.\n",
180 *bug_id
, READ_ONCE(per_cpu(cur_csd_func
, cpux
)),
181 READ_ONCE(per_cpu(cur_csd_info
, cpux
)));
183 pr_alert("\tcsd: CSD lock (#%d) %s.\n",
184 *bug_id
, !cpu_cur_csd
? "unresponsive" : "handling this request");
187 if (!trigger_single_cpu_backtrace(cpu
))
190 pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id
, raw_smp_processor_id(), cpu
);
191 arch_send_call_function_single_ipi(cpu
);
201 * csd_lock/csd_unlock used to serialize access to per-cpu csd resources
203 * For non-synchronous ipi calls the csd can still be in use by the
204 * previous function call. For multi-cpu calls its even more interesting
205 * as we'll have to ensure no other cpu is observing our csd.
207 static __always_inline
void csd_lock_wait(call_single_data_t
*csd
)
212 ts1
= ts0
= sched_clock();
214 if (csd_lock_wait_toolong(csd
, ts0
, &ts1
, &bug_id
))
218 smp_acquire__after_ctrl_dep();
222 static void csd_lock_record(call_single_data_t
*csd
)
226 static __always_inline
void csd_lock_wait(call_single_data_t
*csd
)
228 smp_cond_load_acquire(&csd
->node
.u_flags
, !(VAL
& CSD_FLAG_LOCK
));
232 static __always_inline
void csd_lock(call_single_data_t
*csd
)
235 csd
->node
.u_flags
|= CSD_FLAG_LOCK
;
238 * prevent CPU from reordering the above assignment
239 * to ->flags with any subsequent assignments to other
240 * fields of the specified call_single_data_t structure:
245 static __always_inline
void csd_unlock(call_single_data_t
*csd
)
247 WARN_ON(!(csd
->node
.u_flags
& CSD_FLAG_LOCK
));
250 * ensure we're all done before releasing data:
252 smp_store_release(&csd
->node
.u_flags
, 0);
255 static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t
, csd_data
);
257 void __smp_call_single_queue(int cpu
, struct llist_node
*node
)
260 * The list addition should be visible before sending the IPI
261 * handler locks the list to pull the entry off it because of
262 * normal cache coherency rules implied by spinlocks.
264 * If IPIs can go out of order to the cache coherency protocol
265 * in an architecture, sufficient synchronisation should be added
266 * to arch code to make it appear to obey cache coherency WRT
267 * locking and barrier primitives. Generic code isn't really
268 * equipped to do the right thing...
270 if (llist_add(node
, &per_cpu(call_single_queue
, cpu
)))
271 send_call_function_single_ipi(cpu
);
275 * Insert a previously allocated call_single_data_t element
276 * for execution on the given CPU. data must already have
277 * ->func, ->info, and ->flags set.
279 static int generic_exec_single(int cpu
, call_single_data_t
*csd
)
281 if (cpu
== smp_processor_id()) {
282 smp_call_func_t func
= csd
->func
;
283 void *info
= csd
->info
;
287 * We can unlock early even for the synchronous on-stack case,
288 * since we're doing this from the same CPU..
290 csd_lock_record(csd
);
292 local_irq_save(flags
);
294 csd_lock_record(NULL
);
295 local_irq_restore(flags
);
299 if ((unsigned)cpu
>= nr_cpu_ids
|| !cpu_online(cpu
)) {
304 __smp_call_single_queue(cpu
, &csd
->node
.llist
);
310 * generic_smp_call_function_single_interrupt - Execute SMP IPI callbacks
312 * Invoked by arch to handle an IPI for call function single.
313 * Must be called with interrupts disabled.
315 void generic_smp_call_function_single_interrupt(void)
317 flush_smp_call_function_queue(true);
321 * flush_smp_call_function_queue - Flush pending smp-call-function callbacks
323 * @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an
324 * offline CPU. Skip this check if set to 'false'.
326 * Flush any pending smp-call-function callbacks queued on this CPU. This is
327 * invoked by the generic IPI handler, as well as by a CPU about to go offline,
328 * to ensure that all pending IPI callbacks are run before it goes completely
331 * Loop through the call_single_queue and run all the queued callbacks.
332 * Must be called with interrupts disabled.
334 static void flush_smp_call_function_queue(bool warn_cpu_offline
)
336 call_single_data_t
*csd
, *csd_next
;
337 struct llist_node
*entry
, *prev
;
338 struct llist_head
*head
;
341 lockdep_assert_irqs_disabled();
343 head
= this_cpu_ptr(&call_single_queue
);
344 entry
= llist_del_all(head
);
345 entry
= llist_reverse_order(entry
);
347 /* There shouldn't be any pending callbacks on an offline CPU. */
348 if (unlikely(warn_cpu_offline
&& !cpu_online(smp_processor_id()) &&
349 !warned
&& !llist_empty(head
))) {
351 WARN(1, "IPI on offline CPU %d\n", smp_processor_id());
354 * We don't have to use the _safe() variant here
355 * because we are not invoking the IPI handlers yet.
357 llist_for_each_entry(csd
, entry
, node
.llist
) {
358 switch (CSD_TYPE(csd
)) {
361 case CSD_TYPE_IRQ_WORK
:
362 pr_warn("IPI callback %pS sent to offline CPU\n",
367 pr_warn("IPI task-wakeup sent to offline CPU\n");
371 pr_warn("IPI callback, unknown type %d, sent to offline CPU\n",
379 * First; run all SYNC callbacks, people are waiting for us.
382 llist_for_each_entry_safe(csd
, csd_next
, entry
, node
.llist
) {
383 /* Do we wait until *after* callback? */
384 if (CSD_TYPE(csd
) == CSD_TYPE_SYNC
) {
385 smp_call_func_t func
= csd
->func
;
386 void *info
= csd
->info
;
389 prev
->next
= &csd_next
->node
.llist
;
391 entry
= &csd_next
->node
.llist
;
394 csd_lock_record(csd
);
397 csd_lock_record(NULL
);
399 prev
= &csd
->node
.llist
;
407 * Second; run all !SYNC callbacks.
410 llist_for_each_entry_safe(csd
, csd_next
, entry
, node
.llist
) {
411 int type
= CSD_TYPE(csd
);
413 if (type
!= CSD_TYPE_TTWU
) {
415 prev
->next
= &csd_next
->node
.llist
;
417 entry
= &csd_next
->node
.llist
;
420 if (type
== CSD_TYPE_ASYNC
) {
421 smp_call_func_t func
= csd
->func
;
422 void *info
= csd
->info
;
424 csd_lock_record(csd
);
427 csd_lock_record(NULL
);
428 } else if (type
== CSD_TYPE_IRQ_WORK
) {
429 irq_work_single(csd
);
433 prev
= &csd
->node
.llist
;
438 * Third; only CSD_TYPE_TTWU is left, issue those.
441 sched_ttwu_pending(entry
);
444 void flush_smp_call_function_from_idle(void)
448 if (llist_empty(this_cpu_ptr(&call_single_queue
)))
451 local_irq_save(flags
);
452 flush_smp_call_function_queue(true);
453 if (local_softirq_pending())
456 local_irq_restore(flags
);
460 * smp_call_function_single - Run a function on a specific CPU
461 * @func: The function to run. This must be fast and non-blocking.
462 * @info: An arbitrary pointer to pass to the function.
463 * @wait: If true, wait until function has completed on other CPUs.
465 * Returns 0 on success, else a negative status code.
467 int smp_call_function_single(int cpu
, smp_call_func_t func
, void *info
,
470 call_single_data_t
*csd
;
471 call_single_data_t csd_stack
= {
472 .node
= { .u_flags
= CSD_FLAG_LOCK
| CSD_TYPE_SYNC
, },
478 * prevent preemption and reschedule on another processor,
479 * as well as CPU removal
481 this_cpu
= get_cpu();
484 * Can deadlock when called with interrupts disabled.
485 * We allow cpu's that are not yet online though, as no one else can
486 * send smp call function interrupt to this cpu and as such deadlocks
489 WARN_ON_ONCE(cpu_online(this_cpu
) && irqs_disabled()
490 && !oops_in_progress
);
493 * When @wait we can deadlock when we interrupt between llist_add() and
494 * arch_send_call_function_ipi*(); when !@wait we can deadlock due to
495 * csd_lock() on because the interrupt context uses the same csd
498 WARN_ON_ONCE(!in_task());
502 csd
= this_cpu_ptr(&csd_data
);
508 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
509 csd
->node
.src
= smp_processor_id();
513 err
= generic_exec_single(cpu
, csd
);
522 EXPORT_SYMBOL(smp_call_function_single
);
525 * smp_call_function_single_async(): Run an asynchronous function on a
527 * @cpu: The CPU to run on.
528 * @csd: Pre-allocated and setup data structure
530 * Like smp_call_function_single(), but the call is asynchonous and
531 * can thus be done from contexts with disabled interrupts.
533 * The caller passes his own pre-allocated data structure
534 * (ie: embedded in an object) and is responsible for synchronizing it
535 * such that the IPIs performed on the @csd are strictly serialized.
537 * If the function is called with one csd which has not yet been
538 * processed by previous call to smp_call_function_single_async(), the
539 * function will return immediately with -EBUSY showing that the csd
540 * object is still in progress.
542 * NOTE: Be careful, there is unfortunately no current debugging facility to
543 * validate the correctness of this serialization.
545 int smp_call_function_single_async(int cpu
, call_single_data_t
*csd
)
551 if (csd
->node
.u_flags
& CSD_FLAG_LOCK
) {
556 csd
->node
.u_flags
= CSD_FLAG_LOCK
;
559 err
= generic_exec_single(cpu
, csd
);
566 EXPORT_SYMBOL_GPL(smp_call_function_single_async
);
569 * smp_call_function_any - Run a function on any of the given cpus
570 * @mask: The mask of cpus it can run on.
571 * @func: The function to run. This must be fast and non-blocking.
572 * @info: An arbitrary pointer to pass to the function.
573 * @wait: If true, wait until function has completed.
575 * Returns 0 on success, else a negative status code (if no cpus were online).
577 * Selection preference:
578 * 1) current cpu if in @mask
579 * 2) any cpu of current node if in @mask
580 * 3) any other online cpu in @mask
582 int smp_call_function_any(const struct cpumask
*mask
,
583 smp_call_func_t func
, void *info
, int wait
)
586 const struct cpumask
*nodemask
;
589 /* Try for same CPU (cheapest) */
591 if (cpumask_test_cpu(cpu
, mask
))
594 /* Try for same node. */
595 nodemask
= cpumask_of_node(cpu_to_node(cpu
));
596 for (cpu
= cpumask_first_and(nodemask
, mask
); cpu
< nr_cpu_ids
;
597 cpu
= cpumask_next_and(cpu
, nodemask
, mask
)) {
602 /* Any online will do: smp_call_function_single handles nr_cpu_ids. */
603 cpu
= cpumask_any_and(mask
, cpu_online_mask
);
605 ret
= smp_call_function_single(cpu
, func
, info
, wait
);
609 EXPORT_SYMBOL_GPL(smp_call_function_any
);
611 static void smp_call_function_many_cond(const struct cpumask
*mask
,
612 smp_call_func_t func
, void *info
,
613 bool wait
, smp_cond_func_t cond_func
)
615 struct call_function_data
*cfd
;
616 int cpu
, next_cpu
, this_cpu
= smp_processor_id();
619 * Can deadlock when called with interrupts disabled.
620 * We allow cpu's that are not yet online though, as no one else can
621 * send smp call function interrupt to this cpu and as such deadlocks
624 WARN_ON_ONCE(cpu_online(this_cpu
) && irqs_disabled()
625 && !oops_in_progress
&& !early_boot_irqs_disabled
);
628 * When @wait we can deadlock when we interrupt between llist_add() and
629 * arch_send_call_function_ipi*(); when !@wait we can deadlock due to
630 * csd_lock() on because the interrupt context uses the same csd
633 WARN_ON_ONCE(!in_task());
635 /* Try to fastpath. So, what's a CPU they want? Ignoring this one. */
636 cpu
= cpumask_first_and(mask
, cpu_online_mask
);
638 cpu
= cpumask_next_and(cpu
, mask
, cpu_online_mask
);
640 /* No online cpus? We're done. */
641 if (cpu
>= nr_cpu_ids
)
644 /* Do we have another CPU which isn't us? */
645 next_cpu
= cpumask_next_and(cpu
, mask
, cpu_online_mask
);
646 if (next_cpu
== this_cpu
)
647 next_cpu
= cpumask_next_and(next_cpu
, mask
, cpu_online_mask
);
649 /* Fastpath: do that cpu by itself. */
650 if (next_cpu
>= nr_cpu_ids
) {
651 if (!cond_func
|| cond_func(cpu
, info
))
652 smp_call_function_single(cpu
, func
, info
, wait
);
656 cfd
= this_cpu_ptr(&cfd_data
);
658 cpumask_and(cfd
->cpumask
, mask
, cpu_online_mask
);
659 __cpumask_clear_cpu(this_cpu
, cfd
->cpumask
);
661 /* Some callers race with other cpus changing the passed mask */
662 if (unlikely(!cpumask_weight(cfd
->cpumask
)))
665 cpumask_clear(cfd
->cpumask_ipi
);
666 for_each_cpu(cpu
, cfd
->cpumask
) {
667 call_single_data_t
*csd
= per_cpu_ptr(cfd
->csd
, cpu
);
669 if (cond_func
&& !cond_func(cpu
, info
))
674 csd
->node
.u_flags
|= CSD_TYPE_SYNC
;
677 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
678 csd
->node
.src
= smp_processor_id();
681 if (llist_add(&csd
->node
.llist
, &per_cpu(call_single_queue
, cpu
)))
682 __cpumask_set_cpu(cpu
, cfd
->cpumask_ipi
);
685 /* Send a message to all CPUs in the map */
686 arch_send_call_function_ipi_mask(cfd
->cpumask_ipi
);
689 for_each_cpu(cpu
, cfd
->cpumask
) {
690 call_single_data_t
*csd
;
692 csd
= per_cpu_ptr(cfd
->csd
, cpu
);
699 * smp_call_function_many(): Run a function on a set of other CPUs.
700 * @mask: The set of cpus to run on (only runs on online subset).
701 * @func: The function to run. This must be fast and non-blocking.
702 * @info: An arbitrary pointer to pass to the function.
703 * @wait: If true, wait (atomically) until function has completed
706 * If @wait is true, then returns once @func has returned.
708 * You must not call this function with disabled interrupts or from a
709 * hardware interrupt handler or from a bottom half handler. Preemption
710 * must be disabled when calling this function.
712 void smp_call_function_many(const struct cpumask
*mask
,
713 smp_call_func_t func
, void *info
, bool wait
)
715 smp_call_function_many_cond(mask
, func
, info
, wait
, NULL
);
717 EXPORT_SYMBOL(smp_call_function_many
);
720 * smp_call_function(): Run a function on all other CPUs.
721 * @func: The function to run. This must be fast and non-blocking.
722 * @info: An arbitrary pointer to pass to the function.
723 * @wait: If true, wait (atomically) until function has completed
728 * If @wait is true, then returns once @func has returned; otherwise
729 * it returns just before the target cpu calls @func.
731 * You must not call this function with disabled interrupts or from a
732 * hardware interrupt handler or from a bottom half handler.
734 void smp_call_function(smp_call_func_t func
, void *info
, int wait
)
737 smp_call_function_many(cpu_online_mask
, func
, info
, wait
);
740 EXPORT_SYMBOL(smp_call_function
);
742 /* Setup configured maximum number of CPUs to activate */
743 unsigned int setup_max_cpus
= NR_CPUS
;
744 EXPORT_SYMBOL(setup_max_cpus
);
748 * Setup routine for controlling SMP activation
750 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
751 * activation entirely (the MPS table probe still happens, though).
753 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
754 * greater than 0, limits the maximum number of CPUs activated in
758 void __weak
arch_disable_smp_support(void) { }
760 static int __init
nosmp(char *str
)
763 arch_disable_smp_support();
768 early_param("nosmp", nosmp
);
770 /* this is hard limit */
771 static int __init
nrcpus(char *str
)
775 if (get_option(&str
, &nr_cpus
) && nr_cpus
> 0 && nr_cpus
< nr_cpu_ids
)
776 nr_cpu_ids
= nr_cpus
;
781 early_param("nr_cpus", nrcpus
);
783 static int __init
maxcpus(char *str
)
785 get_option(&str
, &setup_max_cpus
);
786 if (setup_max_cpus
== 0)
787 arch_disable_smp_support();
792 early_param("maxcpus", maxcpus
);
794 /* Setup number of possible processor ids */
795 unsigned int nr_cpu_ids __read_mostly
= NR_CPUS
;
796 EXPORT_SYMBOL(nr_cpu_ids
);
798 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
799 void __init
setup_nr_cpu_ids(void)
801 nr_cpu_ids
= find_last_bit(cpumask_bits(cpu_possible_mask
),NR_CPUS
) + 1;
804 /* Called by boot processor to activate the rest. */
805 void __init
smp_init(void)
807 int num_nodes
, num_cpus
;
810 cpuhp_threads_init();
812 pr_info("Bringing up secondary CPUs ...\n");
814 bringup_nonboot_cpus(setup_max_cpus
);
816 num_nodes
= num_online_nodes();
817 num_cpus
= num_online_cpus();
818 pr_info("Brought up %d node%s, %d CPU%s\n",
819 num_nodes
, (num_nodes
> 1 ? "s" : ""),
820 num_cpus
, (num_cpus
> 1 ? "s" : ""));
822 /* Any cleanup work */
823 smp_cpus_done(setup_max_cpus
);
827 * Call a function on all processors. May be used during early boot while
828 * early_boot_irqs_disabled is set. Use local_irq_save/restore() instead
829 * of local_irq_disable/enable().
831 void on_each_cpu(smp_call_func_t func
, void *info
, int wait
)
836 smp_call_function(func
, info
, wait
);
837 local_irq_save(flags
);
839 local_irq_restore(flags
);
842 EXPORT_SYMBOL(on_each_cpu
);
845 * on_each_cpu_mask(): Run a function on processors specified by
846 * cpumask, which may include the local processor.
847 * @mask: The set of cpus to run on (only runs on online subset).
848 * @func: The function to run. This must be fast and non-blocking.
849 * @info: An arbitrary pointer to pass to the function.
850 * @wait: If true, wait (atomically) until function has completed
853 * If @wait is true, then returns once @func has returned.
855 * You must not call this function with disabled interrupts or from a
856 * hardware interrupt handler or from a bottom half handler. The
857 * exception is that it may be used during early boot while
858 * early_boot_irqs_disabled is set.
860 void on_each_cpu_mask(const struct cpumask
*mask
, smp_call_func_t func
,
861 void *info
, bool wait
)
865 smp_call_function_many(mask
, func
, info
, wait
);
866 if (cpumask_test_cpu(cpu
, mask
)) {
868 local_irq_save(flags
);
870 local_irq_restore(flags
);
874 EXPORT_SYMBOL(on_each_cpu_mask
);
877 * on_each_cpu_cond(): Call a function on each processor for which
878 * the supplied function cond_func returns true, optionally waiting
879 * for all the required CPUs to finish. This may include the local
881 * @cond_func: A callback function that is passed a cpu id and
882 * the info parameter. The function is called
883 * with preemption disabled. The function should
884 * return a blooean value indicating whether to IPI
886 * @func: The function to run on all applicable CPUs.
887 * This must be fast and non-blocking.
888 * @info: An arbitrary pointer to pass to both functions.
889 * @wait: If true, wait (atomically) until function has
890 * completed on other CPUs.
892 * Preemption is disabled to protect against CPUs going offline but not online.
893 * CPUs going online during the call will not be seen or sent an IPI.
895 * You must not call this function with disabled interrupts or
896 * from a hardware interrupt handler or from a bottom half handler.
898 void on_each_cpu_cond_mask(smp_cond_func_t cond_func
, smp_call_func_t func
,
899 void *info
, bool wait
, const struct cpumask
*mask
)
903 smp_call_function_many_cond(mask
, func
, info
, wait
, cond_func
);
904 if (cpumask_test_cpu(cpu
, mask
) && cond_func(cpu
, info
)) {
907 local_irq_save(flags
);
909 local_irq_restore(flags
);
913 EXPORT_SYMBOL(on_each_cpu_cond_mask
);
915 void on_each_cpu_cond(smp_cond_func_t cond_func
, smp_call_func_t func
,
916 void *info
, bool wait
)
918 on_each_cpu_cond_mask(cond_func
, func
, info
, wait
, cpu_online_mask
);
920 EXPORT_SYMBOL(on_each_cpu_cond
);
922 static void do_nothing(void *unused
)
927 * kick_all_cpus_sync - Force all cpus out of idle
929 * Used to synchronize the update of pm_idle function pointer. It's
930 * called after the pointer is updated and returns after the dummy
931 * callback function has been executed on all cpus. The execution of
932 * the function can only happen on the remote cpus after they have
933 * left the idle function which had been called via pm_idle function
934 * pointer. So it's guaranteed that nothing uses the previous pointer
937 void kick_all_cpus_sync(void)
939 /* Make sure the change is visible before we kick the cpus */
941 smp_call_function(do_nothing
, NULL
, 1);
943 EXPORT_SYMBOL_GPL(kick_all_cpus_sync
);
946 * wake_up_all_idle_cpus - break all cpus out of idle
947 * wake_up_all_idle_cpus try to break all cpus which is in idle state even
948 * including idle polling cpus, for non-idle cpus, we will do nothing
951 void wake_up_all_idle_cpus(void)
956 for_each_online_cpu(cpu
) {
957 if (cpu
== smp_processor_id())
960 wake_up_if_idle(cpu
);
964 EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus
);
967 * smp_call_on_cpu - Call a function on a specific cpu
969 * Used to call a function on a specific cpu and wait for it to return.
970 * Optionally make sure the call is done on a specified physical cpu via vcpu
971 * pinning in order to support virtualized environments.
973 struct smp_call_on_cpu_struct
{
974 struct work_struct work
;
975 struct completion done
;
982 static void smp_call_on_cpu_callback(struct work_struct
*work
)
984 struct smp_call_on_cpu_struct
*sscs
;
986 sscs
= container_of(work
, struct smp_call_on_cpu_struct
, work
);
988 hypervisor_pin_vcpu(sscs
->cpu
);
989 sscs
->ret
= sscs
->func(sscs
->data
);
991 hypervisor_pin_vcpu(-1);
993 complete(&sscs
->done
);
996 int smp_call_on_cpu(unsigned int cpu
, int (*func
)(void *), void *par
, bool phys
)
998 struct smp_call_on_cpu_struct sscs
= {
999 .done
= COMPLETION_INITIALIZER_ONSTACK(sscs
.done
),
1002 .cpu
= phys
? cpu
: -1,
1005 INIT_WORK_ONSTACK(&sscs
.work
, smp_call_on_cpu_callback
);
1007 if (cpu
>= nr_cpu_ids
|| !cpu_online(cpu
))
1010 queue_work_on(cpu
, system_wq
, &sscs
.work
);
1011 wait_for_completion(&sscs
.done
);
1015 EXPORT_SYMBOL_GPL(smp_call_on_cpu
);